1. Field of the Invention
The present invention is related to a guiding structure for regulating a traveling direction of a swing arm in an arcuate motion, particularly, related to a guiding structure of a swing arm applicable to a taking out robot for swiftly and precisely taking a molded product out of a die used in an injection molding machine.
2. Description of the Related Arts
As well known, an injection-molding machine is provided with a molding die having both a fixed die and a movable die in the prior art. A molded product is produced by being interposed between the fixed and movable dies, and is taken out of the movable die at a high speed by a taking out machine such as a taking out robot when the movable die is separated from the fixed die. Specifically, this type of taking out robot has a swinging arm (referred to as a swing arm) with absorbing means at an end thereof for detachably holding the molded product. During the operation of injection molding the swing arm is retracted from the molding die. Upon taking out the molded product from the movable die, the swing arm rotatably travels to a predetermined position from a retracted position along a prescribed plane of rotation. Successively, the swing arm linearly travels in a thrust direction parallel to a rotary axis of the swing arm nearby the molded product to hold it with the absorbing means. As soon as the molded product is held with the absorbing means, the swing arm linearly returns in the thrust direction to the prescribed plane of rotation. Successively, the swing arm rotates to a taking out position where the molded product is detached from the absorbing means. Thus, the molded product is taken out of the molding die of the injection-molding machine.
In such a taking out robot mentioned above, the rotary motion and the successive thrust motion of the swing arm were performed independently by using a couple of servomotors in the prior art. Here, in order to take out the molded product at a high speed or to save the access time of the swing arm, the thrust motion of the swing arm is started before the rotary motion ceases. Thus, the motion of the swing arm includes an arcuate motion, which is a superimposed motion of the rotary and thrust motions.
However, upon driving the injection molding machine at high speeds, it is difficult to perform a precise arcuate motion of the swing arm at high speeds by driving the couple of servomotors synchronously, resulting in that the absorbing means of the swing arm can not reach a desired or correct position on the objective molded product. Thus, it is impossible to take the molded product out of the movable die in the injection-molding machine. Further, from a viewpoint of a production cost, it is disadvantageous to use the couple of servomotors because it requires more electric and mechanical components and a more complicated structure.
Accordingly, it is a general object of the present invention to provide a guiding structure for regulating a traveling direction of a swing arm in which the above disadvantages have been eliminated.
More specific object of the present invention to provide a guiding structure for regulating a traveling direction of a swing arm comprising: a swing arm; rotating means having a rotary axis; and converting means provided along the rotary axis of the rotating means for transmitting a rotary force caused by the rotating means to the swing arm and for regulating a traveling direction of the swing arm in accordance with a prescribed traveling path; wherein a traveling direction of the swing arm is regulated by the converting means from a rotary direction to a thrust direction parallel to the rotary axis through an arcuate motion.
Further more specific object of the present invention to provide a taking out robot for taking out a molded product from an injection molding machine comprising: a base; rotating means having a rotary shaft; a cylindrical cam slidably provided on the rotary shaft, the cylindrical cam being formed with a first cam groove and a second cam groove thereon; a first cam follower fixed on a side of the base to engage with the first cam follower; a second cam follower connected to a side of the rotary means to engage with the second cam groove; and a swing arm having absorbing means at one end thereof for detachably holding the molded product from the injection molding machine, the swing arm being connected to one end of the cylindrical cam, wherein the cylindrical cam is driven by an engagement of the second cam groove and the second cam follower so that a motion of the cylindrical cam is regulated by the engagement of the first cam groove and the first cam follower, and the motion of the cylindrical cam is transmitted to the swing arm.
Another specific object of the present invention is to provide an injection molding machine comprising: a molding die having a movable die and a fixed die for molding a molded product interposed between the fixed die and the movable die; control means for separating the movable die from the fixed die; and a taking out robot for taking out the molded product; the taking out robot comprising: a base; rotating means having a rotary shaft; a cylindrical cam slidably provided on the rotary shaft, the cylindrical cam being formed with a first cam groove and a second cam groove thereon; a first cam follower fixed on a side of the base to engage with the first cam follower; a second cam follower connected to a side of the rotary means to engage with the second cam groove; and a swing arm having absorbing means at one end thereof for detachably holding the molded product from the injection molding machine, the swing arm being connected to one end of the cylindrical cam; wherein the cylindrical cam is driven by an engagement of the second cam groove and the second cam follower so that a motion of the cylindrical cam is regulated by the engagement of the first cam groove and the first cam follower, and the motion of the cylindrical cam is transmitted to the swing arm so that the absorbing means of the swing arm detachably holds the molded product from the molded product.